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Colonization and Decolonization of MRSA. Ed Septimus, MD, FIDSA, SHEA, FACP eseptimus@gmail.com. Carriage of S. aureus as a Risk Factor for Infection. Surgery - 50 infections in 628 carriers 33 infections in 2962 noncarriers RR 7.1 (4.6-11) Clin Microb Rev 1997; 10:505
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Colonization and Decolonization of MRSA Ed Septimus, MD, FIDSA, SHEA, FACP eseptimus@gmail.com
Carriage of S. aureus as a Risk Factor for Infection • Surgery -50 infections in 628 carriers 33 infections in 2962 noncarriers RR 7.1 (4.6-11) Clin Microb Rev 1997; 10:505 -Orthopedics ICHE 2000; 21:319 -Cardiac J Infect Dis 1995; 171:216
Carriage of S. aureus as a Risk Factor for Infection • Hemodialysis -S. aureus most frequent infection at vascular site or bacteremia -Patients on hemodialysis have ↑ S. aureus carriage rate -Most S. aureus infections are endogeneous RR 1.8-4.7 if a carrier ICHE 1994; 15:78 Am J Kidney Dis 1986; 2:281
Carriage of S. aureus as a Risk Factor for Infection • CAPD -S. aureus leading cause of CAPD related infections -S. aureus nasal carriage is the major risk factor RR 1.8-14 Clin Microbiol Rev 1997; 10:505 Perit Dial Int 1996; 16:352
Carriage of S. aureus as a Risk Factor for Infection • HIV-Positive Patient -Increased rate of S. aureus bacteremia -Nasal carriage is the most important risk factor OR 5.1 Ann Intern Med 1999; 130:221 -Higher carriage rate of S. aureus with progressive HIV (asymptomatic 23.5%; AIDS 50%) Eur J Clin Microbiol Infect Dis 1992; 11:985
Carriage of S. aureus as a Risk Factor for Infection • Intravascular Device-Associated bacteremia -Patients with an IV device who are colonized with S. aureus have a higher rateof S. aureus bacteremia RR 12.4 Am J Med 1996; 100:509 -Nasal carriage of S. aureus was identified by molecular studies to be the source of line related bacteremia N Engl J Med 2001; 344:11
Colonization, Fomites, and Virulence:Rethinking the Pathogenesis of CA-MRSA InfectionClin Infect Dis 2008; 46:752 • CA-MRSA nasal colonization is uncommon; therefore indicating a role for noncolonization route for CA-MRSA transmission • “Five Cs” of CA-MRSA transmission -contact (direct skin-skin contact) -cleanliness -compromised skin integrity -contaminated objects and environment -crowded living
Frequent Contact Crowding Defense Offense Cleanliness Antimicrobial Use Contaminated Surfaces and Shared Items Compromised Skin Factors that Facilitate Transmission
Colonization, Fomites, and Virulence:Rethinking the Pathogenesis of CA-MRSA InfectionClin Infect Dis 2008; 46:752
Epidemiology MSSA and MRSA Reservoirs Humans are the natural reservoirs for S. aureus. 20-50 % of healthy adults are colonized with S. aureus, and 10-20% are persistent carriers. Colonization rates are highest among patients with type 1 diabetes, IV drug users, hemodialysis, dermatologic conditions, and AIDS. Colonized and infected patients are the major reservoir of MRSA.
Epidemiology continued 3. Nasal colonization with MRSA is the single most important determinant of subsequent MRSA infections • Patterns of carriage: persistent 20% (12-30%) intermittent 30% (16-70%) non-carriage 50% (16-69) J Clin Microbiol 1999;37:3133
Epidemiology continued 5.Persistent carriers have higher S. aureus loads and a higher risk of acquiring S. aureus infection Antimicrob Agents Chemo 1963; 161:667 J Clin Microbiol 1999; 37:3133 6.Nasal carriers who are also perineal carriers have higher S. aureus loads and disperse more S. aureus ICHE 2002; 23:495
Role of Nasal Carriage inS. aureus InfectionsLancet Infect Dis 2005; 5:751
Frequency of MRSA Colonization at Various Body Sites 13-25% 40% 30-39% Hill RLR et al. J Antimicrob Chemother 1988;22:377 Sanford MD et al. Clin Infect Dis 1994;19:1123
Evaluation of a Strategy of Screening Multiple Anatomic Sites for MRSA at Admission to a Teaching HospitalInfect Control Hosp Epidemiol 2006; 27:181-184 Site% Positive Nares 73 Rectum 47 Axilla 25 Nares+Axilla 83 Nares+Rectum 91
S. Aureus Intestinal Colonization Associated with Increased Frequency of S. aureus on Skin in Hospitalized PatientsBMC Infect Dis 2007; 7:105
Epidemiology of S. aureus Colonization in Nursing Home ResidentsClin Infect Dis 2008;46: May 1 • 14 community NH in MI from March 2003 to November 2004 • To assess colonization with S. aureus cultures were obtained from nares, oropharynx, PEG site insertion (if present), groin, perianal, and wounds (if present) • Residents with a urinary catheter, a PEG, or central line were enrolled as the device group • An equal number of control residents without devices were randomly selected as controls
Epidemiology of S. aureus Colonization in Nursing Home ResidentsClin Infect Dis 2008;46: May 1
Throat Swabs Are Necessary to Reliably Detect Carriers of S. aureusClin Infect Dis 2007; 45:475 • Samples were obtained from anterior nares and pharynx using separate swabs (2000-2005) • For culture, a selective enrichment broth was inoculated • After overnight incubation, broth was subcultured onto both chromogenic agar for S. aureus and Columbia agar • 37.1% of persons were nasal carriers and 12.8% were solely throat carriers • The additional throat swab increased yield from 37% to almost 50% • 0.74% were MRSA positive
Eradication of MRSA Colonization • Systemic antimicrobials • Topical intranasal mupiricin • Bathing with CHG • Combination therapy What sites of MRSA colonization should be targeted and does it work?
General Comments • Short-term eradication generally successful, but most patients become recolonized later with same strain Arch Intern Med 1994; 154:1505 • Most regiments seem to last up to 90 days; therefore decolonization rather than eradication is a better term Clin Infect Dis 2007; 44:186 • Recolonization rates at 1 year approach 50% for healthy HCW and 75% for patients on PD • Cochrane Database Syst Rev 2003;4 J Kidney Dis 1993; 22:708 • Recolonization rate at 4 months in patients on HD was 56% and recolonization rate was 71% in HIV-positive patients ASAIO J 1995; 41:127 J Infect Dis 1999; 180:896
Impact of Universal IP Surveillance and Decolonization on Rates of HA-MRSA BSI2006 IDSA Abstract # 142 • Nasal PCR MRSA surveillance for all inpatients • Five-day mupiricin/CHG decolonization for carriers • In two-year pre-intervention HA-MRSA BSI was 0.57 and 0.5 per 1000 admissions respectively • Post intervention rate HA-MRSA BSI was 0.2 per 1000 admissions (P=0.02) • BSI rate for other organisms in the two-year pre-intervention was 0.9 and 0.63 per 1000 admissions and 0.63 per 1000 admissions post intervention (P=NS)
Reduction in Incidence of Nosocomial MRSA Infection in an ICU:Role of Treatment with Mupiricin Ointment and CHG Baths for Nasal Carriers ofMRSAICHE 2006; 27:185
Select Use of Intranasal Mupiricin and CHG Bathing and the Incidence of MRSA Colonization and Infection Among ICU PatientsICHE 2007;28:1155
Effectiveness of CHG Bathing to Reduce Catheter-Associated Bloodstream Infections in MICUArch Intern Med 2007; 167:2073
Randomized Controlled Trial of CHG for Washing, Intranasal Mupiricin, and Rifampin and Doxycycline Versus No Treatment for the Eradication of MRSA ColonizationClin Infect Dis 2007; 44:178
Comments • Increased mupiricin use has been associated with increased drug resistance and failure to clear S. aureus Diagn Microbiol Infect Dis 2002; 42:283 • ASC in SICU for MRSA were tested for mupiricin resistance-13.2% were resistant despite low-level in-hospital use Clin Infect Dis 2007; 45:541 • Mupiricin resistance noted in 24% of isolates and an additional 5% after treatment Clin Infect Dis 2007; 44:178 • Frequent adverse effects of systemic antimicrobial therapy with 25% of patients developing GI side effects and 5% discontinuing therapy Clin Infect Dis 2007; 44:178 • Risk of development of drug resistance especially with rifampin Antimicrob Agents Chemother 1993; 37:1334
S. aureus carriage and risk of surgical site infections • Nasal carriage of S. aureus has been consistently identified as a risk factor for development of postoperative surgical site infections in a large number of studies involving different populations Colbeck JC et al. Can Serv Med J 1959; 15: 326-331 Weinstein HJ. New Engl J Med 1959; 260: 1303-1308 Williams REO et al. Br Med J 1959; 2: 658-662
Guidelines for Prevention of Surgical Site infections (SSI), 1999Infect Control Hosp Epidemiol 1999; 20:247Mupirocin No recommendation to preoperatively apply mupirocin to nares to prevent SSI-unresolved issue
Randomized Trial of Prophylactic Mupiricin + CHG ShowerN Engl J Med 2002;346:1871 • Nasal carriage of S. aureus eliminated in 83.4% v. 27.4% in placebo (p<0.001) • SSI 7.9% v. 8.5% (ns) • S. aureus SSI 2.3% v. 2.4% (ns) • In carriers: -any HA staph infection (most SSI) 4% v. 7.7% (OR 7.7% 95% CI 0.25-0.92) -84.6% PFGE match between nares and SSI • All surgical procedures combined-overall infection rate low
Antibiotic Prophylaxis in Cardiac Surgery, Part IISociety of Thoracic Surgeons (STS)www.sts.orgFebruary 2007 Routine mupirocin administration is recommended for all patients undergoing cardiac surgical procedures in the absence of a documented negative testing for Staphylococcal colonization (Level A)
Intranasal Mupiricin Reduces Sternal Wound Infect after Open Heart Surgery in Diabetics and NondiabeticsAnn Thorac Surg 2001; 71:1572 • Prospective study over a 3 year period who were enrolled in two consecutive prospective groups involving use and nonuse of intranasal mupiricin • Overall sternal SSI 2.7% untreated group v. 0.9% in the treatment group (p=0.005) • Not a randomized control study
Prevention of Nosocomial Infection in Cardiac Surgery by Decontamination of the Nasopharynx and Oropharynx with Chlorhexidene Gluconate (CHG)JAMA 2006; 296:2460 • Prospectively, randomized, double-blind, placebo controlled trial in cardiac surgery • Oropharyngeal rinse and nasal ointment containing CHG or placebo • Patients were eligible whenever prolonged ICU stay (>5 days) or prolonged ventilation (> 2 days) was expected after surgery • A significant reduction of 57.5% in S. aureus carriage compared with a reduction of 18.1% in placebo group (P<.001) • SSIs and pneumonias were significantly reduced
Recent LiteratureMupirocin • Prophylactic intranasal mupirocin did not significantly reduce postoperative S. aureus infections (included all procedures) N Engl J Med 2002; 346:1871 • Intranasal mupirocin starting day -1 to day +4 significantly decreased MRSA SSIs in orthopedic surgery J Hosp Infect 2003; 54:196
SSI Infections in Orthopedic SurgeryClin Infect Dis 2002; 35:353 • Preoperative nasal carriage rate S. aureus was ~30% • 614 patients were randomized to receive mupirocin vs. placebo • Eradication of nasal carriage was significantly more effective in the mupirocin group (83.5% vs. 27.8%) • Mupirocin did not reduce SSIs due to S. aureus significantly (3.8% mupirocin group vs. 4.7% in placebo) • In the mupirocin group, the rate of endogenous S. aureus infections was five times lower than in placebo group (ns) • Study was not powered adequately for infections
Recent LiteratureMupirocin cont. • Perioperative intranasal mupiricin decreased SSIs in nongeneral surgery (cardiothoracic and orthopedic) but not in general surgery Infect Control Hosp Epidemiol 2005; 26:916 • Intranasal mupiricin significantly reduced S. aureus SSI rates in cardiac surgery Am J Infect Control 2006; 34:44
Impact of Rapid Molecular Screening for MRSA in Surgical WardsBritish J Surg 2008; 95:381 • In 2006, nasal swabs were obtained before surgery for all patients undergoing elective and emergency procedures by PCR • MRSA-positive patients were started on mupiricin nasal ointment and CHG body wash • Overall 4.5% were MRSA-positive • MRSA bacteremia fell by 38.5% (P<0.001) • MRSA SSIs fell 12.7% ( P=0.031)
Ed’s Current Recommendations • Use of systemic antimicrobial agents or mupiricin to eliminate MRSA carriage is not recommended for the general patient population or for pre-op decolonization for general surgery patients. • Pre-operative decolonization may be considered for MSSA and MRSA-colonized patients about to undergo selected high-risk surgical procedures, such as CV surgery, vascular procedures with placement of a graft, prosthetic joint implantation, and neurosurgical procedures with implantation of hardware.
Ed’s Current Recommendationscontinued • The optimal decolonization regiment is unclear, but mupiricin and CHG is reasonable. • The use of vancomycin for surgical prophylaxis for certain high-risk procedures such as CV surgery, vascular procedures with placement of a graft, prosthetic joint implantation, and nuerosurgical procedures with implantation of hardware, for patients colonized with MRSA should be considered.
No ESKAPE E=Enterococcus faecium S=Staphylococcus aureus K=Klebsiella pneumoniae A=Acinetobacter baumanni P=Pseudomonas aeruginosa E=Enterobacter species Rice; J Infect Dis 2008;April 15
Ed’s SuggestionsMDRO • Adherence to evidenced-based prevention practices -Hand washing and contact precautions -CR-BSI bundle -VAP bundle -SSI bundle -CHG bathing in ICU • Antimicrobial stewardship • Decontamination of environment and equipment • Second tier of interventions based on local epidemiology
Burden of HAIs in the U.S., 2002 • 1.7 million infections in hospitals • Most (1.3 million) were outside of ICUs • 4.5 per 100 admissions • 99,000 deaths associated with infection • 36,000 pneumonia; • 31,000 bloodstream infections Klevens, Edwards, Richards, et al. Pub Health Rep 2007;122:160-6
Problem Enhanced by • Antimicrobial resistance • Emerging pathogens • Emergence of novel/virulent strains • Rapid worldwide spread